The Chinese patent application No. 201080006305.3 filed on Jan. 12, 2010 by Microsoft Corporation and entitled “Visual Target Tracking” had proposed a scheme relevant to visual target tracking, where a target was tracked by receiving an observed depth image of the target from a source and obtaining a pose model of the target, the pose model was rasterized into a synthesized depth image, and the pose of the model was then adjusted based, at least in part, on differences between the observed depth image and the synthesized depth image.
In the above-mentioned method, an accurate depth image is required for the subsequent processings, and this accurate depth image may be obtained by a depth camera. However, currently the depth camera with high accuracy is very expensive, e.g., the price of Mesa Imaging SwissRanger 4000 (SR4000) is as high as ten thousands of US dollars.